Telephone intercommunicating system for aeroplanes



Dec. 15', 1925- G. D. EDWARDS ET AL TELEPHONE INTERCOMMUNICATING SYSTEM Fon AERoPLANEs Filed Sent. 25 1920 2 Sheets-Sheefl 1 iL Ml Dec, 15, 1925. 1.565.628 G. D. EDWARDS ET A).

T'ELEHONE IN'IERGOMMUNICATINCT SYSTEM FOR AEROPLANES iled sept. 25. 192@ 2 sheets-sheet 2 Patented Dee 15,1925..

GEORGE D. EDWARDS, OF EAST ORANGE, AND

LAKES, NEW JERSEY, ASSIGNORS `T WILLIAM H. CAPEN, 0F MOUNTAIN WESTERN ELECTRIC COMPANY, INCORPO- RATED, OF NEW YORK, N. Y., ACORPORATION OF NEW YORK.

TELEIHONE INTERCOMMUNICATING SYSTEM SFOR AEROPLANE S.

Application led September 25, 1920. Serial N o. 412,864.

To all whom t may concern.'

Be it known that we, GEORGE D..EDwARDs and WILLIAM H. vCAPEN, citizens of the United States, residing at East Orange vand Mountain Lakes, in the counties of Essex and Morris, respectively, State of New .J ersey, have invented certain new and luseful Improvements in Telephone Intercommunicatmg Systems for Aeroplanes, of which i `the lfollowing is a full clear, concise, and

exact description. y

This invention relates to poly-station communication systems and more particularly to communication systems for use on aircraft and the like, for local intercommunication and for distant radio signaling.

An object of the invention is to provide a communication system which will permit a radio operator on an aircraft to` keep in communication with a distant radio' station, and at the same time to receive any necessary instructions from other members of his crew.

Another object of the invention is to provide a radio telephone system to permit one member of an airplane crew to. carry-on telephone conversation with a distant point and to permit other members of the crew to listen in on the conversation..

A further object of the invention is to .provide a ely-station intercommunication system which will4 permit one station to carry on radio communication with a 'dis-- tant point, and to permit two or more local stations to intercommunicate with each other at the same time, without interfering withthe radio communication.

Al further-object of the invention is to provide aflexible poly-station signaling ar- 40 rangement, the number of stations of which can be readily increased without changing the circuit arrangements.

A still further object ofthe inventionis to provide a poly-station intercommunication system in which a single induction `coil may serve forall of the stations.

An additional object of the invention is to provide a poly-station signaling systemV which maybe built up of weatherproof units to operate under severe weather conditions,

as, for example, in seaplanes.

` According to this invention, a poly-station system isbuilt up by associating with radio transmitting and receiving apparatus a plurality of stations, rone of which is adapted to operate with the radio apparatus and all of which are arranged for intercommunication with each other. The master station, from which the radio apparatus is controlled, may switch over at will into the local intercommunicating system. An 0perator at one of the other local estations may connect his communicating circuits to the master station receiver either when the latter is in its open neutral position or when it'is operating in conjunction with the radio apparatus. This local station operator may then listen in on incoming radio messages or may talk to the master station operator without causing speech to .be transmitted out by the radio ap aratns. Y

In the drawing, Figure l is a diagram of lthe circuit arrangements, and FiO'ure 2 is a perspective view of the units ciD a threestation airplane set. p Referring to. Figure l, the radio apparatus is illustrated as comprising separate receiving andtransmitting antennae, radio receiving apparatus RA, and transmitting apparatus T Associated with this kapparatus are three operators stations,-the master station M, and the two local stations A tnd B,-each indicated as a whole, in dotted ines.

The master station M is equipped with a double throw switch KM which, if thrown to the left, connects the `set to the radio apparatus, and if thrown to the right connects it to the interphone circuit conductors l, 2 and 4, of which, `conductors l and 2 comprise the listening circuit and 2 and 4 the talking circuit. The master station also includes the primary winding P of an induction coil, which is permanently connected in series with a talking battery E across conductors 2 and 4, and the secondary winding S of the induction coil is permanently connected to conductors 1 and 2.

The local stations A and B each comprise a receiver R and a series condenser, permanently connected to the listening circuit conductors, and a transmitter T in a normally open circuit across the talking conductors. This open circuit may be closed at will by means` of a double through switch K. A conductor 3 is provided for communication with the master station. If a switch K is thrown to the right, it connects its transmitter to the two talking conductors 2am] 4, it to the left, it connects the transmitter to both the talking conductors andY the conductor In operation, it the operator at the master station desires to engage in radio communication, he throws his switch KM to the left. I he Wishes to communicate with either of the local stations, he throws this switch to the right, thus connecting his receiver and transmitter across the listening and talking circuits, respectively. It one of the local station operators desires to listen in on the received radio communication, he throws his switch K to the left. This connects his receiver in shunt to the master station receiver. If he desires to break in on the conversation he may do so, since his transmitter circuit is closed. His remarks to the master station operator will not be transmitted out by the radio apparatus since his transmitter is entirely disconnected from the radio transmission circuit. y

The local station operators may engage in conversation with each other, regardless of whether or not the master station operator .is operating his radio-apparatus. When a local station operator throws his switch K to the right and talks, the other local operators, whose receivers are directly connected across the listening conductors, receive the communication. To respond, another operator likewise throws his own switch K to the right. The master operator may connect his set in on this intercommunicating line at any time by moving his own switch KM to the right. It will be evident that the master operator may be in continuous radio comuninication with a distant station and at the same time the other members of the crew may listen in, or, without disturbing the radio conversation, may communicate with each other. At any time, they are in position to communicate with the master operator.

Whenever local communication is carried on, the microphone is in circuit with source E and primary winding P of the induction coil. This primary winding is inductively associated with winding S ot the induction coil and telephone currents are repeated to the listening circuit connected to this Winding. This enables a single two-winding induction coil to be used and the local station units can therefore be made very compact, llVhen the various switches K are each in neutral position, there is no drain on the source E.

In Figure 2, the various units of the apparatus are shown in an assembly perspective,-tl1e radio apparatus unit H, the master station unit M, and the local station units A and B, the master station having jacks marked T and R for connection with the transmitting and receiving circuit cords, respectively, ot' the succeeding unit and the stations A and B each having similar jacks for connection with the operators transmitter and head set cords. The apparatus is accordingly so designed that it may be associated with any standard radio equipment, it being merely. necessary to install the master unit and as many local stations as desired and to connect each by a simple cord extension connection to the preceding unit. Each unit may be made weatlierproof and the system may be readily extended as the need arises.y

Although this invention has been described as embodied in a telephone system, it is obviously not so limited in its application since it is equally suitable for both telegraph and other forms of signaling. Certain features of the invention are applicable to intercommunication systems generally, without regard to aircraft or radio telephony, and it is therefore to be understood that the invention is to be limited only by the scope of the appended claims.

WVhat is claimed is:

1. An intercommunicating system, comprising a master station set, and a plurality of local stations, each having a transmitter and receiver, means whereby said master station may engage in two-Way communicationA with a distant station, and simultaneously each of said local stations may transmit to and receive from all of the other local stations, and means whereby said master station may listen in at will on the receiver circuits of all of the local stations together and each of the local stations may listen in on the master station, said means comprising a single circuit-closing means at each station.

2. A communicating system comprising radio apparatus, a plurality of local Signal stations, a master station, means for enabling an operator at said master station to engage in two-way radio communication with a distant station, and means for enabling said local stations during the radio communication to communicate with each other and to have one-way communication with said master station including means excluding the signal currents originating at the local stations from the radio transmitting apparatus at the master station.

3. An intercommunicating system, comprising a radio transmitting and receiving apparatus, a master station set having a transmitter and receiver opera-tively associated therewith, and an additional set having means to listen in on the master station receiver circuit, and to transmit signals thereto during radio transmission including means excluding currents of said local communciations from the radio transmitting apparatus at the master station.

4. A n aircraft communication system, comprising a master operators signaling 'set and a. plurality'of local 'station operators sets, means whereby the master operator may eugage'in distant radio -communication and simultaneously the local station operators ma engage inV local intercommunication, an means wherebyeither said master operator or one of said local station operators may at will listen in on the receiving circuit oftheother. 'M' .f

5. An intercommunicating system, comprising a master stationset, .and a plurality of local stations, each having a4 transmitter and receiver, means whereby said master station may engage in two-way communication with a distant statlon, and simultaneously Said local stations may engage in two-Way communication with each other, means whereby said master station may listen-in on the receiver circuits of all of the local .stations simultaneously, the means whereby each of saidlocal stations may listen-in on the receiving circuits of said master station and .simultaneousl on the receiver circuits of all of the remaining local stations.

Inrwitness whereof, We hereunto subscribe our names this22nd day of September A. D.a 1920.

GEORGE D. EDWARDS. WILLIAM H. CAPEN. 

